// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/time/time.h"

#include <limits>
#include <ostream>

#include "base/float_util.h"
// #include "base/lazy_instance.h"
// #include "base/logging.h"
// #include "base/third_party/nspr/prtime.h"

namespace base {

// TimeDelta ------------------------------------------------------------------

// static
TimeDelta TimeDelta::Max() {
    return TimeDelta(std::numeric_limits<int64>::max());
}

int TimeDelta::InDays() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int>::max();
    }
    return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);
}

int TimeDelta::InHours() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int>::max();
    }
    return static_cast<int>(delta_ / Time::kMicrosecondsPerHour);
}

int TimeDelta::InMinutes() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int>::max();
    }
    return static_cast<int>(delta_ / Time::kMicrosecondsPerMinute);
}

double TimeDelta::InSecondsF() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<double>::infinity();
    }
    return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond;
}

int64 TimeDelta::InSeconds() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int64>::max();
    }
    return delta_ / Time::kMicrosecondsPerSecond;
}

double TimeDelta::InMillisecondsF() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<double>::infinity();
    }
    return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond;
}

int64 TimeDelta::InMilliseconds() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int64>::max();
    }
    return delta_ / Time::kMicrosecondsPerMillisecond;
}

int64 TimeDelta::InMillisecondsRoundedUp() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int64>::max();
    }
    return (delta_ + Time::kMicrosecondsPerMillisecond - 1) /
        Time::kMicrosecondsPerMillisecond;
}

int64 TimeDelta::InMicroseconds() const {
    if (is_max()) {
        // Preserve max to prevent overflow.
        return std::numeric_limits<int64>::max();
    }
    return delta_;
}

// Time -----------------------------------------------------------------------

// static
Time Time::Max() {
    return Time(std::numeric_limits<int64>::max());
}

// static
Time Time::FromTimeT(time_t tt) {
    if (tt == 0)
        return Time();  // Preserve 0 so we can tell it doesn't exist.
    if (tt == std::numeric_limits<time_t>::max())
        return Max();
    return Time((tt * kMicrosecondsPerSecond) + kTimeTToMicrosecondsOffset);
}

time_t Time::ToTimeT() const {
    if (is_null())
        return 0;  // Preserve 0 so we can tell it doesn't exist.
    if (is_max()) {
        // Preserve max without offset to prevent overflow.
        return std::numeric_limits<time_t>::max();
    }
    if (std::numeric_limits<int64>::max() - kTimeTToMicrosecondsOffset <= us_) {
        //DLOG(WARNING) << "Overflow when converting base::Time with internal " << "value " << us_ << " to time_t.";
        return std::numeric_limits<time_t>::max();
    }
    return (us_ - kTimeTToMicrosecondsOffset) / kMicrosecondsPerSecond;
}

// static
Time Time::FromDoubleT(double dt) {
    if (dt == 0 || IsNaN(dt))
        return Time();  // Preserve 0 so we can tell it doesn't exist.
    if (dt == std::numeric_limits<double>::infinity())
        return Max();
    return Time(static_cast<int64>((dt *
        static_cast<double>(kMicrosecondsPerSecond)) +
        kTimeTToMicrosecondsOffset));
}

double Time::ToDoubleT() const {
    if (is_null())
        return 0;  // Preserve 0 so we can tell it doesn't exist.
    if (is_max()) {
        // Preserve max without offset to prevent overflow.
        return std::numeric_limits<double>::infinity();
    }
    return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
        static_cast<double>(kMicrosecondsPerSecond));
}

#if defined(OS_POSIX)
// static
Time Time::FromTimeSpec(const timespec& ts) {
    return FromDoubleT(ts.tv_sec +
        static_cast<double>(ts.tv_nsec) /
        base::Time::kNanosecondsPerSecond);
}
#endif

// static
Time Time::FromJsTime(double ms_since_epoch) {
    // The epoch is a valid time, so this constructor doesn't interpret
    // 0 as the null time.
    if (ms_since_epoch == std::numeric_limits<double>::infinity())
        return Max();
    return Time(static_cast<int64>(ms_since_epoch * kMicrosecondsPerMillisecond) +
        kTimeTToMicrosecondsOffset);
}

double Time::ToJsTime() const {
    if (is_null()) {
        // Preserve 0 so the invalid result doesn't depend on the platform.
        return 0;
    }
    if (is_max()) {
        // Preserve max without offset to prevent overflow.
        return std::numeric_limits<double>::infinity();
    }
    return (static_cast<double>(us_ - kTimeTToMicrosecondsOffset) /
        kMicrosecondsPerMillisecond);
}

int64 Time::ToJavaTime() const {
    if (is_null()) {
        // Preserve 0 so the invalid result doesn't depend on the platform.
        return 0;
    }
    if (is_max()) {
        // Preserve max without offset to prevent overflow.
        return std::numeric_limits<int64>::max();
    }
    return ((us_ - kTimeTToMicrosecondsOffset) /
        kMicrosecondsPerMillisecond);
}

// static
Time Time::UnixEpoch() {
    Time time;
    time.us_ = kTimeTToMicrosecondsOffset;
    return time;
}

Time Time::LocalMidnight() const {
    Exploded exploded;
    LocalExplode(&exploded);
    exploded.hour = 0;
    exploded.minute = 0;
    exploded.second = 0;
    exploded.millisecond = 0;
    return FromLocalExploded(exploded);
}

// static
bool Time::FromStringInternal(const char* time_string,
    bool is_local,
    Time* parsed_time) {
    if (!((time_string != NULL) && (parsed_time != NULL)))
        DebugBreak();

    if (time_string[0] == '\0')
        return false;

    //   PRTime result_time = 0;
    //   PRStatus result = PR_ParseTimeString(time_string,
    //                                        is_local ? PR_FALSE : PR_TRUE,
    //                                        &result_time);
    //   if (PR_SUCCESS != result)
    //     return false;
    // 
    //   result_time += kTimeTToMicrosecondsOffset;
    //   *parsed_time = Time(result_time);
    DebugBreak();
    return true;
}

// Local helper class to hold the conversion from Time to TickTime at the
// time of the Unix epoch.
class UnixEpochSingleton {
public:
    UnixEpochSingleton()
        : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}

    TimeTicks unix_epoch() const { return unix_epoch_; }

private:
    const TimeTicks unix_epoch_;

    DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);
};

// static LazyInstance<UnixEpochSingleton>::Leaky
//     leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;

// Static
TimeTicks TimeTicks::UnixEpoch() {
    //return leaky_unix_epoch_singleton_instance.Get().unix_epoch();
    DebugBreak();
    return TimeTicks::Now();
}

// Time::Exploded -------------------------------------------------------------

inline bool is_in_range(int value, int lo, int hi) {
    return lo <= value && value <= hi;
}

bool Time::Exploded::HasValidValues() const {
    return is_in_range(month, 1, 12) &&
        is_in_range(day_of_week, 0, 6) &&
        is_in_range(day_of_month, 1, 31) &&
        is_in_range(hour, 0, 23) &&
        is_in_range(minute, 0, 59) &&
        is_in_range(second, 0, 60) &&
        is_in_range(millisecond, 0, 999);
}

}  // namespace base
